Bug 109252 - external monitor flicker with error [drm:intel_dp_get_link_train_fallback_values [i915]] *ERROR* Link Training Unsuccessful
Summary: external monitor flicker with error [drm:intel_dp_get_link_train_fallback_val...
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
Depends on:
Reported: 2019-01-09 05:39 UTC by alex.tu
Modified: 2019-01-18 09:25 UTC (History)
4 users (show)

See Also:
i915 platform:
i915 features:

the dmesg got after issue happened. (152.03 KB, text/plain)
2019-01-09 05:39 UTC, alex.tu
no flags Details
dmesg from drm-tip 2019-01-18 (10.75 MB, text/plain)
2019-01-18 09:25 UTC, Kai-Heng Feng
no flags Details

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Description alex.tu 2019-01-09 05:39:20 UTC
Created attachment 143026 [details]
the dmesg got after issue happened.

VGA of Host Machine: 
00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:3e9b] (prog-if 00 [VGA controller])

Monitor:  Dell P2317H (can also reproduce it on other monitor)

steps to reproduce:
1. connect external monitor 
2. see screen on external monitor
3. get flicker on external monitor
4. switch display mode by "windows+p" still get flicker or even dark screen.
5. see error message on dmesg
[drm:intel_dp_get_link_train_fallback_values [i915]] *ERROR* Link Training Unsuccessful
Comment 1 alex.tu 2019-01-09 10:24:43 UTC
this issue could be also reproduced by main line kernel 5.0.0-rc1
Comment 2 Radosław Szwichtenberg 2019-01-11 10:02:45 UTC
Please try to reproduce the error using drm-tip (https://cgit.freedesktop.org/drm-tip) and kernel parameters drm.debug=0x1e log_buf_len=4M, and if the problem persists attach the full dmesg from boot.
Comment 3 Kai-Heng Feng 2019-01-18 09:25:24 UTC
Created attachment 143148 [details]
dmesg from drm-tip 2019-01-18

No more "[drm:intel_dp_get_link_train_fallback_values [i915]] *ERROR* Link Training Unsuccessful" but I still observe the issue.

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